Bob Diamond, Barclays president and one of the highest paid bankers in the UK, has claimed the imposition of a bonus tax would be against the remuneration principles agreed at the G20 meeting held in September.His comments come just a day after the chancellor told him and a group of other senior bank figures that they needed to be able to justify their living to their neighbours."You have to pass the next-door neighbour test," Darling told the bankers last night, while discussing their possible contributions to a new small firm bank."You have to be able to look at your next-door neighbour and justify what you are doing," he said.The meeting yesterday, which also included Business Secretary Lord Mandelson, was to sound out the willingness of the large banks to contribute millions of pounds to a new government-backed fund that will lend to Britain's small businesses.The chancellor's comments come amid fevered speculation that the government may impose a bonus tax on the sector in tomorrow's pre-Budget speech, a possibility that has already come under heavy fire from all quarters of the City.Adding his voice to the disquiet, Diamond told a conference today, "We don't feel that that is supported by the principles that were adopted (at the G20)". "It's extremely important today that around the large economies and financial centres that we create a level playing field around capital, accounting and compensation". "I support strongly New York and London as financial centres and we all have an interest in keeping them both strong," he added.